To observe a full moon from Earth, the Moon needs to be positioned directly opposite the Sun, with the Earth in between them. This alignment allows the sunlight to fully illuminate the side of the Moon facing Earth, making it appear fully lit.
In a diagram showing the Sun (A), Earth (B), and Moon (C), the configuration for a full moon would be:
- Sun (A) → Earth (B) → Moon (C) in a straight line.
Look for the diagram where the Sun is on one side, the Earth is in the middle, and the Moon is on the opposite side, indicating a full moon phase.